This invention relates generally to data communication using a photographic filmstrip. More particularly, the invention relates to a method and apparatus for recording data on a photographic filmstrip.
It is recognized that images provide a superior means for exchanging information quickly and efficiently. However, there is a vast array of data that is associated with an image that can be used to increase the quality and utility of the image. For example, image processing algorithms exist that use data concerning the image such as camera settings, the distance between the camera and the subject, and/or whether a flash was discharged, to improve the appearance of an image. In addition, data concerning the image can be used to facilitate communication between a photographer and a photofinisher allowing the photographer to identify the number and type of prints of the image to be produced by a photofinisher. Further, the image itself becomes more useful to the user when the image is associated with data indicating the date, time, location and subject of the image, thus permitting the user to more quickly locate an image of interest. The image can also be made more useful to the consumer where the image is associated with multimedia data such as audio and other information.
Information of this type is known as metadata. Metadata is a term that is used to describe data that is associated with an image but may not necessarily visually appear in the image. The most convenient and effective way to gather and associate metadata with an image is to automatically associate metadata with the image at the time the image is captured and processed. For the full benefits of metadata to be realized, a method is needed to efficiently define metadata, to associate metadata with an image, and to later access and update the metadata.
A number of systems for accomplishing this result have been developed. Two of these systems have involved recording metadata magnetically on a magnetic recording layer of a photographic filmstrip and recording metadata optically on a photosensitive layer of a photographic filmstrip.
1. Magnetic Recording
In the early 1960s, an innovation in data communication for motion picture film was introduced. A thin layer of magnetic oxide, referred to as a DATAKODE Magnetic Control Surface, was coated across the entire back surface of a roll of motion picture film to provide the capability to magnetically record digital data on the film without interfering with normal photographic use of the film. The DATAKODE Magnetic Control Surface permitted recording of different types of digital data at different stages of production of a motion picture. Such data could range from camera lighting and filter data at the time of exposure, to printer exposure control information in the laboratory, to theatre automation control signals during exhibition. The DATAKODE Magnetic Control Surface was specifically applied to the recording of time code on motion picture films.
During the 1980s, film information exchange systems using dedicated magnetic tracks were developed for use in still photography. In these systems, a virtually transparent magnetic layer on the still photography filmstrip facilitates the magnetic recording of metadata in one or more longitudinal tracks of each film frame. With a virtually transparent magnetic layer, metadata recording may be done everywhere on the film including in the image area, so that metadata could be recorded with each frame of the film. In order to provide quick access to particular metadata at any stage of film use, related metadata is preferably grouped and recorded in specific predetermined tracks. In one of these systems for example, camera metadata, for example, is recorded in several dedicated longitudinal tracks along the filmstrip edges. The camera data, as well as other data, is preferably recorded in pulse position encoded form in order to be independent of film transport velocity.
Commonly assigned U.S. Pat. No. 5,204,708 describes an approach for recording metadata on a filmstrip using a simple, low cost camera, in which metadata is incorporated into metadata fields that are recorded in magnetic tracks on the film. This approach is used in the recently introduced Advanced Photographic System (APS). In APS, redundant copies of important metadata fields are recorded on a magnetic recording track associated with the image. Each track has a track start sentinel and a track end sentinel.
APS specifications limit the types of metadata that can be recorded to a predefined set of metadata elements. This set includes a minimum set of elements known as required metadata elements, and an optional set of metadata elements known as selectable metadata elements. Required metadata elements include, for example, the date and time that an image is captured and the format of the image. Selectable metadata includes, for example, a title that is associated with an image.
APS cameras that record metadata on film must record at least the required metadata in association with each image. Selectable metadata elements can be recorded where the camera that captures the image is adapted with features that generate the selectable metadata. The existing APS metadata recording architecture does not accommodate metadata types that are not within the pre-defined set of required and selectable metadata elements.
2. Optical Metadata Encoding Systems
Optical metadata encoding systems have been known for many years. Such systems have permitted a camera user or a camera to optically encode words, symbols, or other markings onto a photographic image. Typically, the principal use of such systems has been to provide user readable markings. In commonly assigned U.S. Pat. No. 5,666,186, an apparatus and method are shown for automatically extracting data from user readable markings on a filmstrip and for modifying the portion of the image containing the user data to improve the appearance of the image.
In another recent system for optically recording data in an image, it has been proposed to hide or embed information within an image using a technique known as watermarking. In this technique, metadata is embedded in the picture itself using a random phase carrier. The random phase carrier is designed so that the embedded metadata is encoded in the image in a visually transparent manner so that while the picture is modified, it does not appear to have been modified. This technique permits data to be optically encoded onto a filmstrip and later extracted from the processed image. In such optical metadata encoding systems, the requirement that the data is encoded in a visually transparent or visually pleasing manner can limit the amount of metadata that can be recorded in the image. Further, there exists a risk that optically encoded metadata can be lost or misinterpreted. Accordingly, a preferred architecture metadata is redundantly recorded in metadata fields that are optically recorded in the image.
As photographic technology continues to improve, new camera and image processing capabilities are introduced and existing capabilities are enhanced. Many of these capabilities require new forms of metadata that must be communicated using the filmstrip. Further, as existing camera features are enhanced, new and enlarged types of metadata are required. However, photographic film has a fixed capacity to store metadata recorded in either the magnetic or optical format. Thus, a need exists for a method for recording metadata that can accommodate an increased variety and volume of metadata using the same fixed amount of storage space on the film.
A further need exists for a method and camera to record new metadata elements in a manner that will permit existing metadata reading equipment to extract metadata from a filmstrip having new and enlarged types of metadata recorded on it.
A method is provided for recording metadata elements using a predetermined portion of a photographic filmstrip. The method comprises the steps of recording a primary data field including the entire set of data elements using a first share of the predetermined portion; and recording at least two secondary data fields on a second share of the predetermined portion; wherein at least one of the secondary data fields contains less than all of the metadata elements associated with an image.
According to another aspect of the present invention, a method for recording a variable number of metadata elements associated with an image using a predetermined portion of photographic filmstrip is provided. The method comprises the steps of forming a primary data field including the entire set of metadata elements for recording on a first share of the predetermined portion. A determination is made as to whether there is sufficient recording capacity to record all of the metadata elements in each of the secondary metadata fields on a second share of the predetermined portion. At least two secondary metadata fields including the entire set of metadata elements are recorded on the second share where it is determined that there is sufficient recording capacity and at least two secondary data fields are recorded in a second share of the predetermined portion and, wherein at least one of the secondary data fields contains less than all of the metadata elements associated with an image where it is determined that there is insufficient recording capacity.
In another aspect of the present invention, a camera is provided for communicating metadata elements associated with an image using a predetermined portion of a photographic filmstrip. The camera comprises a writing head for recording metadata elements onto a filmstrip. The camera further comprises a controller adapted to compose a pattern of more than two metadata fields including a primary metadata field having all of the metadata elements for recording on a first share of the predetermined portion and at least two secondary metadata fields for recording on a second share of the predetermined portion where at least one of the secondary metadata fields contains less than all of the metadata elements associated with an image, and further adapted to cause the writing head to record the primary and secondary metadata fields on the filmstrip.
In still another aspect of the present invention, a camera is provided for communicating metadata elements associated with an image using a predetermined portion of a photographic filmstrip. The camera comprises at least one camera input, wherein the number of metadata elements associated with the image varies in accordance with the status of the at least one camera input and a writing head for recording metadata elements onto a filmstrip. The camera further comprises a controller adapted to sense the status of the at least one camera input and to compose a pattern of more than two metadata fields including a primary data field including the all of the metadata elements associated with an image for recording on a first share of the predetermined portion; and further composing secondary metadata fields by determining whether there is sufficient recording capacity to record all of the metadata elements in each of the secondary metadata fields on a second share of the predetermined portion and composing at least two secondary metadata fields including the entire set of metadata elements in the second share where it is determined that there is sufficient recording capacity; and composing at least two secondary data fields in the unused share of the predetermined portion, wherein at least one of the secondary data fields contains less than all of the metadata elements associated with an image, where it is determined that there is insufficient recording capacity. The controller is further adapted to cause the writing head to record the composed primary and secondary metadata elements on the photographic filmstrip.
In another aspect of the present invention, a method for recording a set of metadata elements using a predetermined storage capacity of a memory associated with photographic filmstrip is provided. The method comprises the steps of recording a primary data field including the entire set of metadata elements using a first share of the predetermined capacity, recording at least two secondary metadata fields in a second share of the predetermined storage capacity wherein at least one of the secondary data fields contains less than all of the metadata elements.
In another aspect of the present invention, an apparatus for extracting metadata from a photographic filmstrip is provided. The apparatus comprises a read head engaging with the filmstrip and a controller operating the read head to read metadata recorded on the filmstrip, wherein the controller operates the read head to read each metadata field recorded on the filmstrip and to extract metadata from the metadata field having the greatest number of metadata elements.